1. Field of the Invention
The present invention relates to a communication method and apparatus for performing communications using data transmission means which can simultaneously transmit an audio signal and data.
2. Related Background Art
In recent years, owing to the downsizing of computers such as notebook type personal computers and with the advent of electronic stock control and slip process systems using, e.g., POS systems, information in an office can be accessed using a notebook type personal computer or a special-purpose handy terminal via a communication line during sales activity (out) time away from the office. As a result, information acquisition and stock confirmation at a customer site can be easily realized, and a quick response to a customer's need can be attained.
An actual sales person connects a notebook type personal computer or handy terminal to a modem (a PCMCIA card or unit) and a portable telephone, and makes a telephone call to a host computer or a personal computer in his or her office so as to exchange data. Furthermore, recently, electronic devices such as pen computers incorporating a portable telephone function are commercially available.
These electronic devices can be used for managing personal schedules and address books in addition to original jobs such as sales activities. Since information is electrically processed, when personal information such as a schedule of a particular sales person directly heard from him or her is stored in a notebook type personal computer or a portable electronic device, a third party can access this information to confirm his or her schedule and/or to make an appointment on behalf of this sales person. Furthermore, facsimile (FAX) data which has been conventionally output onto a paper sheet can be read on a display screen or can be easily transmitted using a FAX server or a FAX system using a personal computer. For this reason, in addition to a one-way access in which a sales person at a remote location performs confirmation of a received order or a stock, it is often required to send data from an office to the location of the person so as to renew his or hew personal schedule or to send FAX data to this person.
As a background for such requirements, an environment for personal use of electronic devices has been established since high-performance, compact, and low-cost devices have become commercially available, and the area of spread of information has increased due to a widened service area and lower cost of wireless telephones.
A conventional modem (a data or FAX modem) modulates data to transmit digital data onto an analog telephone line for transmitting an audio signal. For this reason, when data is transmitted, a normal speech communication is disabled. However, a modem which can simultaneously transmit audio and data signals (data and FAX) by a time-division or double-carrier method when two stations use identical modems has been recently developed.
However, not to mention a case wherein a modem which can send only data is used, even when a modem which can simultaneously transmit data and audio signals is used, a user cannot know the state of data transmission while performing a speech communication. Therefore, operability is poor. When a speech communication and a data communication are simultaneously performed for different purposes, the progresses of the two communications often contradict with each other.
In addition, not to mention a case wherein a modem which can send only data is used, even when a modem which can simultaneously transmit data and audio signals is used, as described above, a user must perform an operation for sending data while making a speech communication, resulting in poor operability. Furthermore, even when data is renewed in a portable device or a host computer in an office, data is not renewed unless a user makes a telephone call to renew the data.